语法与词汇 The development of the transistor and integrated circuits revolutionized the electronics industry by allowing components to be packaged more (densely).
【正确答案】 A
【答案解析】分析：根据dense的基本含义“密集的”判断B(便宜地)，C(很快地)和D(仔细地)都不是答案，所以答案是A(紧凑地，紧密地)是答案。